The role of segmental bioelectrical impedance technique in the assessment of intraperitoneal ultrafiltration volume with peritoneal dialysis patients

Abstract

Objective: To investigate the role of segmental bioelectrical impedance technique (SBIA) in the assessment of intraperitoneal ultrafiltration volume with peritoneal dialysis patients.

Method: We selected the patients at the Department of Nephrology of the First Affiliated Hospital of Zhengzhou University and measured the segmental bioelectrical impedance by a German Fresenius body composition analyzer (the Fresenius whole body composition measurement (BCM) machine was used as a segmental machine in this study). An alternating current (5 kHz, 0.05-0.7 mA) was continuously released during the measurement. The released current penetrated the peritoneal cavity on both sides of the body, from which the segmental resistance at a frequency of 5 kHz was obtained from the multifrequency data (R5/Ω). Baseline BIA measurements were initiated after the patient entered the supine position for 5-10 min, then dialysate was instilled into the peritoneal cavity. BIA measurements were performed at 10-min intervals during the retention of dialysate in the abdomen and finally ended when dialysate drainage was complete. Real-time intraperitoneal volume estimated by SBIA (IPV_SBIA)and ultrafiltration volume estimated by SBIA(UFV_SBIA) was calculated. At the same time, the actual ultrafiltration volume at the end of peritoneal dialysis was weighed and measured (UFV_MEA).

Results: A total of 30 patients were included in the study, 9 patients withdrew from the study due to subjective factors during the measurement process, and 21 patients completed the study. The correlation coefficient R² of UFV_SBIA and UFV_MEA was 0.21 (p < 0.05). Bland-Altman analysis showed that the bias of UFV_SBIA to the actual UFV_MEA was 0.12 L, and the 95% agreement limit was between -0.5 L and 0.74 L, which confirmed that UFV_SBIA measured by electrical impedance method and UFV_MEA measured by weighing method were in good agreement. The time required to reach the maximum ultrafiltration volume (UFV_SBIA) was 108 ± 68 min, and the mean value of the maximum ultrafiltration volume (Max UFV_SBIA) was 1.16 ± 0.60 L.

Conclusion: The segmental bioelectrical impedance technique can be used to assess the intraperitoneal ultrafiltration volume of peritoneal dialysis patients in real-time and effectively. This method may guide the dialysis fluid retention time and the maximum ultrafiltration volume in PD patients.

Keywords: Segmental bioelectrical impedance technique; peritoneal dialysis; ultrafiltration.